1. Field of the Invention
The present invention relates to an image quality enhancement circuit and method of enhancing an image quality using correlativity between frames, and more particularly, to an image quality enhancement circuit and method of enhancing an image quality by adaptively compensating for a luminance signal based on correlativity between frames.
2. Description of the Related Art
A histogram equalization of various methods for contrast enhancements is widely known. In general, the histogram equalization has an effect on stretching a dynamic range of an image so as to distribute gradations of resultant images flat, thereby enhancing a contrast of images.
Such widely known characteristics of the histogram equalization turn out as defects in some practical occasions. That is, a constant output density of the histogram equalization brings an average brightness of output images closer to a middle gray level.
In the known histogram equalization, a transfer function is independently calculated for and applied to every frame regardless of correlativity between adjacent frames. Such an application of the conventional histogram equalization provides a contrast-enhanced effect to the images when the correlativity between the adjacent frames becomes low, but the application of the conventional histogram equalization may cause a problem of degrading an image quality when a correlation value becomes high. For example, a flicker phenomenon, by which a display changes its brightness from bright to dark, occurs in a case that a current frame shows a particular object that does not exist on a previous frame while the previous and current frames have the same background image.